Question

3 x square - 22 X + 40 = 0

Answer 1

1.1    x3+x2-22x-40  is not a perfect cube 

Trying to factor by pulling out :

 1.2      Factoring:  x3+x2-22x-40 

Thoughtfully split the expression at hand into groups, each group having two terms :

Group 1:  -22x-40 
Group 2:  x3+x2 

Pull out from each group separately :

Group 1:   (11x+20) • (-2)
Group 2:   (x+1) • (x2)

Answer 2

${3x}^{2} - 22x + 40 = 0 \\ {3x}^{2} - 12x - 10x + 40 = 0 \\ 3x(x - 4) - 10(x - 4) = 0 \\( x - 4)(3x - 10) = 0 \\ (x - 4) = 0 \: or \: (3x - 10) = 0 \\ x = 4 \: or \: x = \frac{10}{3}$